Tire pressure monitoring system

Abstract

A tire pressure monitoring system includes a tire valve stem mounted tire pressure gauge and an externally powerable remote display unit. The pressure gauge includes a pressure sensor, a wake circuit, a processor, and a first radio frequency (RF) module. The remote display unit includes a second RF module and a display. The wake circuit is adapted to activate the processor periodically at a predetermined interval of time and causes the processor to receive an output signal from the pressure sensor. The output of the pressure sensor is indicative of a tire pressure detected by the pressure sensor. The remote display unit is adapted to display the measured tire pressure value without any user input.

What is claimed is: 
     
       1. A tire pressure monitoring system comprising:
 at least one tire pressure gauge configured to be mounted on a valve-stem of a tire comprising:
 a radio frequency (RF) transmit/receive module for sending and receiving data indicative of a tire pressure wirelessly via a two-way wireless communication; 
 a first processor; 
 a first memory in communication with said first processor; and 
 a pressure sensor configured for detecting a tire pressure of a tire and for transmitting a signal containing a value indicative of the detected tire pressure to said first processor; 
 wherein said first processor is configured to store the value indicative of the detected tire pressure in said first memory and to instruct said first RF transmit/receive module to transmit a wireless signal containing data indicative of the tire pressure detected by said pressure sensor; and 
 wherein said first processor is configured to instruct said first RF transmit/receive module to transmit a wireless signal only when the value of a tire pressure detected by said pressure sensor differs from a previous tire pressure value stored in said first memory by an amount exceeding a threshold value; 
 
 a remote display unit comprising:
 a second RF transmit/receive module configured for two-way wireless communication with said first RF transmit/receive module; 
 a second processor in communication with said second RF transmit/receive module; 
 a second memory in communication with said second processor; and 
 a display in communication with said second processor and configured to display data indicative of a tire pressure received from said first RF transmit/receive module, said display comprising:
 at least one first graphical element corresponding to a tire, said at least one graphical element configured to display data indicative of a tire pressure of said corresponding tire to a user; 
 a second graphical element configured to display a plurality of pressure units for selection by a user, wherein selection of a pressure unit by a user causes said first processor to instruct said at least one first graphical element to display the tire pressure of the corresponding tire in the selected pressure unit; and 
 at least one third graphical element corresponding to the tire, said at least one third graphical element comprising a graphical bar configured to render a color display corresponding to a tire pressure status of said corresponding tire to a user, said graphical bar including at least a first portion configured to generate a green display corresponding to the tire pressure status of the corresponding tire being within an acceptable range of a pre-set pressure threshold as determined by said first processor, and a second portion configured to generate a red display corresponding to the tire pressure status of the corresponding tire being outside of the acceptable range of the pre-set pressure threshold as determined by said first processor. 
 
 
 
     
     
       2. The tire pressure monitoring system of  claim 1 , wherein said at least one tire pressure gauge further comprises:
 a temperature sensor in communication with said first processor, said temperature sensor configured to detect an internal temperature of a tire and transmit a signal indicative of the detected temperature to said first processor, 
 wherein said first processor is configured to instruct said first RF transmit/receive module to transmit a wireless signal containing data indicative of the internal tire temperature detected by said temperature sensor. 
 
     
     
       3. The tire pressure monitoring system of  claim 2 , wherein said data relating to the tire comprises:
 an identifier indicative of a position or location of the tire; 
 a pressure value indicative of the pressure detected by said pressure sensor; and 
 a temperature value indicative of the internal temperature detected by said temperature sensor. 
 
     
     
       4. The tire pressure monitoring system of  claim 2 , wherein the display is further configured to display data relating to tire pressure and tire temperature, wherein said first graphical element is further configured to display:
 an identifier of said corresponding tire; 
 a tire pressure value of a detected tire pressure of said corresponding tire; and 
 a tire temperature value of a detected temperature of said corresponding tire. 
 
     
     
       5. The tire pressure monitoring system of  claim 4 , wherein said display further comprises:
 a fourth graphical element configured to display a plurality of temperature units for selection by a user, wherein selection of a temperature unit by a user causes said first processor to instruct said at least one first graphical element to display a temperature of the corresponding tire in the selected temperature unit. 
 
     
     
       6. The tire pressure monitoring system of  claim 1 , wherein said pressure sensor comprises:
 a first pressure sensing die in fluid communication with said valve-stem of said tire, said first pressures sensing die configured to detect a tire pressure; and 
 a second pressure sensing die in fluid communication with an atmosphere outside the tire, said second pressure sensing die configured to detect an ambient pressure outside the tire; 
 wherein said pressure sensor is configured to transmit a signal to said first processor indicative of the detected tire pressure and the detected ambient pressure. 
 
     
     
       7. The tire pressure monitoring system of  claim 1 , wherein said first processor is configured to retrieve data relating to a tire from said second memory and to instruct said first RF transmit/receive module to transmit a wireless signal containing the data relating to the tire. 
     
     
       8. The tire pressure monitoring system of  claim 1 , wherein said at least one tire pressure gauge further comprises:
 a wake circuit, said wake circuit in communication with said first RF transmit/receive module, said wake circuit responsive to a wireless signal from said remote display device, generates a wake signal which activates said second processor, which responsive to said wake signal receives a signal indicative of a tire pressure detected by said pressure sensor. 
 
     
     
       9. The tire pressure monitoring system of  claim 1 , wherein said first graphical element further comprises a graphical representation of a strength and/or charge of a battery in said tire pressure gauge.